Publications

We examined the activity pattern of seven ant species (Hymenoptera: Formicidae; Brachymyrmex sp., Camponotus atriceps, Camponotus
integellus, Camponotus sp., Crematogaster nigropilosa, Pheidole biconstricta, and Pheidole sp.) and one wasp species (Hymenoptera: Vespidae; Parachartergus apicalis) tending two treehopper species (Homoptera: Membracidae; Antianthes sp. and Cerosa sp.) on Acnistus
arborescens trees (Solanales: Solanaceae) at San Luis Biological Station in Costa Rica. We observed hymenopteran attendants at 61 of 67
treehopper aggregations. All eight hymenopteran species tended tree-hoppers during the day, but only three of the ant species (C. atriceps, C. nigropilosa, and P. biconstricta) also tended at night. Whereas 23 treehopper aggregations had the same species of ant tending during
both day and night, 19 aggregations had two different attendantspecies, one diurnal and one nocturnal. In all 19 cases, the nocturnal
tender was Camponotus atriceps, a large carpenter ant. Several earlier studies have reported a diel shift in species tending homopterans. In all cases, the nocturnal tender was a species of Camponotus. A possible cause for this diel shift relates to the relatively large body size of
Camponotus workers, which may allow them to displace smaller ants at night, but may be a disadvantage during the day because it makes Camponotus workers a preferred target for diurnal parasites andpredators.
Key words: ants, Camponotus, Costa Rica, diel shifts; Homoptera, Membracidae, myrmecophily, mutualism, Parachartergus, wasp

AI•STRACr.--We studied the behavior and phenology of nesting Elegant Trogons (Trogon elegans) in the Chiricahua, Huachuca, and Santa Rita mountains in southeastern Arizona in 1993 and 1994. We found 34 nests and 11 cavities that were investigated by trogons but never occupied. Adults reared young successfully in 24 nests, but abandoned 5 nests after egg laying; 5 nests had unknown fates. Incubation lasted an average of 19 days; feeding of young lasted 15 days. Nesting phenology was extremely variable: six nests were started in May and contained nestlings or had fledged young by late June; eight nests were started in June and finished by late July; six nests were started in July and had fledged young by late August. Rates and durations of incubation, brooding, and feeding of nestlings were equal between adult male and female trogons except in two cases. Rates between years were different in six cases. Males called significantly more often than females. Elegant Trogons nesting in Arizona have different behaviors from other Neotropical members of the Trogonidae, especially with regards to their durations of incubation and feeding. Also, they feed nestlings insects rather than fruit. Received 24 February 1995, accepted 27 April 1995